Pivotal head for hoisting apparatus.



PATENTED DEC. 31. 1907.

W. H. ARNOLD. PIVOTAL HEAD FOR HOISTING APPARATUS.

' APPLICATION FILED AUG. 8. 1907.

2 SHEETS-SHEET 1.

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W. H. ARNOLD, PIVOTAL HEAD FOR HOISTING APPARATUS.

,APPLIOATION FILED AUG. 8. 1907.

PATENTED DEC. 31, 1907.

2 SHEETS-SHEET WITNESSES: INVENTOR ATTORNEYS THE Mann's PETERS co., umsnmcraw; wc.

WILLIAM H. ARNOLD, OF BROOKLYN, NEW YORK.

PIVOTAL HEAD FOR I-IOISTING APPARATUS.

Specification of Letters Patent.

Patented Dec. 31, 1907.

Application filed August 8, 1907. Serial No. 387,591.

To all whom it may concern:

Be it known that 1, WILLIAM H. ARNOLD, a citizen of the United States, and a resident of Brooklyn, in the county of Kings and State of New. York, have invented certain new and useful Improvements in Pivotal Heads for Hoisting Apparatus, of which the following is a specification.

My invention relates to that class of hoisting apparatus in which a supporting frame or mast is used in connection with a boom, to the out-board end of which the hoisting parts are applied, and more particularly relates to pivotal heads for such apparatus.

The object of my invention is to support the out-board or free end of the boom so that the pull due to the weight of the load will all be transmitted to the center of the pivotal head which supports the free end of the boom.

It has heretofore been the practice to sup port the free end of the boom by connecting it to a pivotal head on the supporting frame or mast by tension rods or other suitable connecting means, which turn with the boom about the pivotal head. These rods have been secured to either side of the boom and to either side of the pivotal head or secured to such head in a manner such that the pull on each rod exerted itself on a different part of the pivot. A grave defect of this construction is that if the load is unequally distributed, that is, if one side of the boom has to support more than the other, one rod will exert a greater pull upon the pivotal head or support for said boom than the other, which exerts a torsional strain in the boom, tending to make it sag and even, in some cases, to break off. According to my invention, thesedefects are overcome by causing the pull of the tension rods or leads due to the load carried by the boom to be exerted upon a common point which in this case may be the center of the pivotal head. Therefore all the load might come upon one side of the boom and there would be no tendency to twist it as the pull would be transmitted to a common point of support for both sides of the boom.

To these ends my invention consists in the preferred form in providing the main supporting frame or post preferably with a ball and socket joint at the top, the ball or pivot being preferably mounted upon the supporting frame and the socket connecting with the free end of the boom through tension rods or leads, which engage the end of the boom at either side thereof. These rods converge and are secured to the socket at places preferably remote from the ball joint proper so that a continuation of the line of one rod would intersect a continuation of the line of the other rod in the center of the ball joint or pivot.

My invention consists further in the various details of construction of the parts as will be hereinafter more particularly described and then set forth in the claims.

My invention will be illustrated and described as used with that form of hoisting apparatus commonly known as a dredge but obviously the same might equally well be applied to other forms of hoisting apparatus without departing from the spirit of my invention.

In the accompanying drawings, Figure 1 illustrates in side elevation a dredging apparatus having my invention applied thereto. Fig. '2 is an enlarged plan view of the top of part of the apparatus shown in Fig. 1. Fig. 3 is an enlarged front elevation of one member of the ball and socket joint. Fig. 4 is an enlarged side elevation of my invention.

Referring to 1, the apparatus is shown as mounted upon a boat or barge 1 and consists of the main support 2 which in the preferred form of apparatus to which my invention is applied would be the usual A frame supported by the ordinary guy ropes or cables 3.

4 indicates the boom mounted upon the turn-table 5 and carrying a dipper or dredgebucket 6 operated by the chains or cables 7 passing through sheaves secured to the free or out-board end of the boom.

The A frame 2 is provided with a pivotal head preferably mounted upon the top of said frame, said head consisting of a pivot preferably of the form of a spherical ball 8 formed upon a casting 9 secured to the side members of the A frame by any suitable means such as by flanges as shown.

A socket preferably formed of the two members 10 and 11 is bolted securely about the circumference of the ball or pivot 8, each member of the socket terminating in an extending arm 10 and 11. The ends of the arms 10 and 11 are provided with converging slots or sockets within which the tension rods or leads 12 and 13 are secured to the arms of the socket. These slots or sockets are so formed that the center lines thereof. if continued would. intersect each other at the center of the pivot or ball ,8. The other ends of the tension rods or leads 12, 13 are preferably secured to the boom in the usual manner, that is, they are fastened to links, said links being secured to the sides of the boom through universal joints as indicated at 15. Obviously the leads 12, 13 might be continued and connected direct with the boom without using the supplementary links shown.

The inner contour of the socket where the same engages the ball or pivot 8 is preferably provided with a wearing surface of Babbitt metal for obvious reasons.

It will thus be seen that the pull on each tension rod or lead due to the load to be hoisted will be exerted upon the same point and there will be no tendency to create a torsional strain in the boom even though one side of the boom is much more heavily loaded than the other.

What I claim as my invention is:

1. In an apparatus of the class described, the combination with the upright support or mast and the boom, of a pivotal head mounted upon said support and leads connecting the out-board end of said boom with said pivotal head, the lines of said leads intersecting in the center of said pivotal head.

2. In an apparatus of the class described, the combination with the upright support or mast and the boom, of a pivotal. head carried by said support and a lead connecting the free end of said boom with said pivotal head, the line of said lead passing through the center of said pivot.

3. In an apparatus of the class described, the combination with the upright support or mast and the boom, of a pivot mounted upon the upright support or mast, a socket adapted to turn upon said pivot and tension rods secured to the free end of said boom and to said socket, said tension' rods converging to the center of said pivot.

4C. In an apparatus of the class described, the combination with the upright support or and the continued line thereof to intersect in the center of the pivotal head.

5. In an apparatus of the class described, the combination with the upright support or mast and the boom, of a pivot mounted upon the upright support, a socket adapted to clamp about said pivot and turn thereon and provided with extending arms, and tension rods secured at one end to the free end of said boom and at the other end of the arms of the socket, said tension rods converging to a point in the center of said pivot.

6. In a dredging apparatus, the combination with the A frame and the boom, of a pivotal head mounted upon said A frame and tension rods connectlng the free end of said boom with the pivotal head, said tension rods converging to the center of said pivotal head.

7. In a dredging apparatus, the combination with the A frame and the boom, of apivot mounted upon the A frame, a socket adapted to turn upon said pivot and provided with extended arms and converging tension rods secured to the outboard end of the boom and to said extended arms, as and for the purpose described.

8. In a dredging apparatus, the combination with the A frame and the boom, of a pivot mounted upon the A frame, a socket provided with extended arms adapted to turn upon said pivot and tension rods connecting the free end of the boom with said extending arms, the line of said tension rods being adapted to intersect inthe center of said pivot, as and for the purpose described.

Signed at New York in the county of New York and State of New York this 10th day of June, A. D. 1907.

WILLIAM H. ARNOLD. 

